Knife for lumber-dressing machinery



. Nov. 8, 1938. WALTMON 2,136,260

KNIFE FOR LUMBER DRESSING MACHINERY Filed Dec. 30. 1956 INVENTOR. .ZIOMA-S J MLr o/v.

ATTORNEYS.

BY Ma Patented Nov. 8, 1938 UNITED 's'm'rizs PATENT OFFICE KNIFE FORLUMBER-DRESSING MACHINERY Thomas J. Waltmon, Portland, Oreg., assignorto The Ohio Knife Company, Cincinnati, Ohio, a

corporation of Ohio Application December 30, 1936,.Seiial No. 118,343

1 Claim.

configurations and surfaces; and the appended claims: isintended torelate to the invention broadly and without restriction to the. specificexemplary embodiment herein described.

The dressing of lumber such, by way of example as a 2 x 4, has usuallybeen carried on in two operations, in each of which a pair of oppositefaces of the piece are simultaneously dressed by cutter heads opposed toeach other. In the usual vertically disposed cutter heads, the knivesare fastened in a drum so as to lie at a large angle to the tangent ofthe drum surface.-

The drum is slotted to receive the knife and suitable clamping means forthe knife are provided. The knives have a back which is corrugated tocoact with a clamping element, and a face which is normally planar.Knives intended for making a straight out are normally beveled from'theface toward the back so that the face sideof the knife is the longest ordeepest side. When the knives are intended to take a shaping ornonplanar cut, it has been the usual practice to groove or machine theback of the knife and then bevel the knife'in the opposite direction,namely, from the back toward the face; there being usually, a meetingbevel of lesser extent in the opposite direction. Therefore, in thisform of knife the back face is the longest or deepest face. Such knives,however, cannot be mounted in the cutter heads as hereinabove described,for the reason that their angularity is wrong. They have to be employedin a cutter head in which the knives are mounted much more nearlytangentially since otherwise the knife edge would tend to scrape andtear the wood.

When eased edge lumber began to be important in the market, the onlyprovision the art made was the provision of knives of the shapingvariety hereinabovediscussed. These knives cannot be employed in theordinary cutter heads. New heads ofa different style had to be purchasedat considerable expense. This made it impossible for the smaller millsin many instances to make eased edge lumber, where new cutter headscould not be afforded.

It is an object of my invention to provide a type of knife suitable formaking a non-planar cut but operable in the ordinary cutter head andinterchangeable with the ordinary knives.

It is an object of my invention to provide. a

knife structure capable of adjustment so as to provide on a given faceof the lumber rounded edges properly spaced apart.

It is an object of my invention to provide a type of knife for thepurpose described which may be sharpened if required without impairing 1the ability of the knife to make the shaping cut.

It is an object of my invention to provide a knife which will havesuitable clearance means for the removal of chips.

These and other objects of my invention, which 1.5:

will be set forth hereinafter or will be apparent to oneupon readingthese specifications, Iaccomplish by that certain construction andarrangement of parts of which I shall now describe the aforesaidexemplary embodiment. 20

Reference is now made to the drawing, wherein,

Fig. 1 is a view in perspective showing a piece of lumber being dressedon its opposite sides by a pair of cutter heads. The table of the planer5 and its appurtenances have not been shown since they are known in theart and do not constitute limitations upon my invention.

Fig.2 shows a blank in perspective from which a knife of my improvedtype may be produced. 30

Fig. 3 is a perspective View of one of the completed knives, and showsalso the filler member.

Fig. 4 is a partial plan View of one of my knives from the face side.

Briefly in the practice of my invention, I pro- 5 vide a knife having ausual corrugated back, and a face side, a portion of which is cut awayso as to lie at a lower plane. When this knife is beveled from the facetoward the back to give a cutting edge, the cutting edge ischaracterized by 4 a rounded shoulder as will be more definitelyhereinafter described. The raised portion of the face is tapered fromthe cutting edge of the knife toward the bottom to give a good chipclearance for cutting. There is a filler plate employed with 45 my knifeto coact with the clamping means and to fill up the cut-away portion ofthe face of the knife over the area of engagement of the clamping meanswith the knife. My knives may be made in rights and lefts and arecapable of 0 use in the ordinary way in the ordinary cutter head asdistinguished from specially made cutter heads. Being made in rights andlofts, each knife operates to plane the face of a piece of lumber and toproduce one eased edge adjacent 5 the face. The next knife also planesthe face and produces the other eased edge. The knives may be adjustedin the cutter head by moving alternate knives in opposite directions soas to gauge the proper distance apart of the eased edges.

I have shown in Fig. l a piece of lumber I, being operated upon by twocutter heads 2 and 3. These cutter heads are generally circular in crosssection as shown and are removably fixed by suitable means 4 and 5, aswell known in the art, to the driving shafts 6 and I. The cutter headsare slotted as at 8 to receive the knives and a side of the slot iscorrugated to engage with the corrugations on the back of the knife. Aclamping block is shown at 9 operating to hold the knife against thecorrugated face of the slot, and controlled by suitable set screws orthe like In and II.

The knife is more clearly shown in Figs. 2, 3 and 4. In Fig. 2 a knifeblank I2 is shown as having a substantially rectangular body. The backface of the knife is corrugated as shown at 13. The front face of theknife has its larger portion M machined or ground down so as to lie in alower plane than a triangularly raised face portion l5. The knife blankis rounded as at 16 between the two planes l4 and IS. The portion! 5tapers as shown, from the cutting edge of the knifetoward the bottomthereof, to give a sufficient clearance for chips. The knife iscompleted by being ground off on a slanting plane I! from the facetoward the back; and. when so ground, the knife will have a cutting edgeas shown in'Fig. 4 of which the larger part lies in a line I 8 at onelevel and a smaller portion in a line [9 at a higher level, there beinga rounded portion 20 between the two plane portions.

The profile of the cutting edge of the knife as shown in Fig. 4, clearlyindicates the type of cut it will make. The portion 20, of course, makesthe eased edge.

I provide, in connection with my knife as shown in Fig. 3, a fillermember 2| to fill out the difference between the planes l4 and I5 of theknife. This is a thin, generally rectangular piece of metal, the edge 22of which, however, is slanted to follow the slant of the rounded portionIQ of the knife and is similarly rounded as at 23. The thickness of themember 2| is sufficient, when the member is laid on the face M, to makethe top edge of it co-planar with the face portion l5. In this way, theclamping member 9 is given an adequate purchase on the knife.

As has been indicated, the knives are made and sold in rights and lefts,which are reverse counterparts of each other. The knives are placed inthe cutter heads in an arrangement consisting of alternate rights andlefts as illustrated in Fig. 1. It will be seen in this figure thatadjustment may readily be made for the dressing of lumber of differentwidths. Thus the knife A may be moved downwardly as indicated by thedotted lines, while the knife B, which is a reverse counterpart of theknife A may be moved upwardly as indicated by the dotted lines, thusmaking provision for the dressing of wider lumber.

The knives may be ground or sharpened in the ordinary Way and willretain their ability to dress eased edge lumber. By reason of theslanting disposition of the curved portion N5 of the knife, it will beclear that as the knife is sharpened away, the rounded cutting edge 20will tend to move somewhat outwardly toward one side of the knife. This,however, is compensated for by adjustment of the knives in the mannerlast hereinabove described.

Modifications may be made in my invention without departing from thespirit of it; and in particular, as will be apparent, knives of the typeherein described and claimed may be used for cutting other types ofconfigurations than the one herein expressly set forth.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

In combination a knife of generally rectangular form having a corrugatedback side and a front side with portions lying at different effectivelevels, said knife being beveled from the front side toward the backside so that the front side is the longer of the two sides, so that thecutting edge of said knife has a configuration other than that of acontinuous straight line, by reason of said different effective levels,and a filler block so shaped that when laid against the front face ofsaid knife it will present an outer surface flush with the highest levelof said front face.

THOMAS J. WALTMON.

